A rollback or bolster is a segment of the seat mounted on hinges and able to pivot from a first position aligned with and forward of the seat to a second position elevated in height above the seat. A marine seat, especially a driver's seat, often is equipped with a bolster so that the driver can see from a higher vantage. This is useful in maneuvering around an obstacle or picking up a line or buoy.
To elevate the seat, the driver will grasp the bolster on either side, raise his weight off the seat, and pivot the bolster upward into the second position. To lower the seat, the driver will again grasp the bolster on either side, raise his weight off the seat, and pivot the bolster downward into the first position. Upon lowering the seat, the driver will allow his weight to drive the seat firmly downward.
The bolster hinge is a four bar linkage having an upper bracket, a lower bracket, and two parallel bars pivotally attached to the brackets. This is shown in FIGS. 15-18. As the hinges pivot from the second position to the first position, the two parallel bars move apart and then move together. In the intermediate positions shown in FIGS. 16 and 17, a significant space opens up between the two parallel bars. One safety problem sometimes encountered with the prior art bolster seats is placement of the hinges at the outer edges of the seat. As the driver grasps the bolster with his fingers underneath, the fingers can slip into the space between the two parallel bars. As the driver's weight impels the bolster downward, the two parallel bars close upon one another, pinching the fingers. The two parallel bars can shear the fingers off. The present invention overcomes this safety hazard, as will be shown hereinbelow.
All vessels operating upon water exhibit six ship motions: Roll is rotation about a fore and aft axis; Pitch is rotation about a transverse axis; Yaw is rotation about a vertical axis; Surge is translation along a fore and aft axis; Sway is translation along a transverse axis; and Heave is translation along a vertical axis. In rough water conditions, a vessel can be thrown about violently in all these directions. Add to these motions the tendency of a planing boat to go airborne over a wave and slam down on the next wave.
Inertial forces generated by the bodyweight of the boat driver are conveyed through the seat to the boat hull. Conversely, forces are transmitted through the seat to the driver. The marine seat must be able to withstand these forces without failure. The seat must also be sufficiently rigid to minimize flexing under inertial forces. Furthermore, the marine seat must be sufficiently resilient to protect the driver from injury due to these forces.
Accordingly, there is a need for a marine seat capable of withstanding inertial forces of ship motion in a seaway.
There is a further need for a marine seat of the type described, and that includes a bolster to provide the driver with a higher vantage viewpoint.
There is a yet further need for a marine seat of the type described, and that will not pinch the driver's fingers causing injury.
There is a still further need for a marine seat of the type described, and that will protect the driver from injury due to inertial forces of a vessel under way.
The present invention is directed toward fulfilling the above-mentioned needs, as well as other needs, and overcoming various disadvantages known in the art.